
public class SimpleCircle
{
    /** Main method */
    public static void main(String[] args)
    {
        //Create a circle with radius 1
        SimpleCircle circle1 = new SimpleCircle();
        System. out. println("The area of the circle of radius "
                             + circle1. radius + " is " + circle1.getArea());
        //Create a circle with radius 25
        SimpleCircle circle2 = new SimpleCircle(25);
        System. out. println("The area of the circle of radius "
                             + circle2. radius + " is " + circle2.getArea());
        //Create a circle with radius 125
        SimpleCircle circle3 = new SimpleCircle(125);
        System. out. println("The area of the circle of radius "
                             + circle3. radius + " is " + circle3.getArea());
        //Modify circle radius
        circle2. radius = 100;
        System. out. println("The area of the circle of radius "
                             + circle2. radius + " is " + circle2.getArea());
    }
    double radius;
    /** Construct a circle with radius 1*/
    SimpleCircle()
    {
        radius = 1;
    }
    /** Construct a circle with a specified radius */
    SimpleCircle(double newRadius)
    {
        radius = newRadius;
    }
    /** Return the area of this circle*/
    double getArea()
    {
        return radius * radius * Math. PI;
    }
    /** Return the perimeter of this circle*/
    double getPerimeter()
    {
        return 2 * radius * Math. PI;
    }
    /** Set a new radius for this circle*/
    void setRadius(double newRadius)
    {
        radius = newRadius;
    }
}
